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91.
锑-槲皮素络合物极谱吸附波的研究 总被引:1,自引:0,他引:1
在1×10~(-2)mol/L。H_2SO_4,1×10~(-5)mol/L。槲皮素,5%乙醇底液中得到了锑-槲皮素络合物还原峰,这是一个明显的络合物吸附极谱波。用其导数波可测定纯As_2O_3中微量Sb。 相似文献
92.
定理1:一维连通无有闭道复形K,在E~2内实现. 定理2:存在一个一维连通复形,有九个一维单形,不能在E~2内实现. 定理3:一维连通复形,有八个一维单形,可在E~2内实现. 定理2,定理3是最好的定理.问题是:n维连通复形(n≥2),相应的定理2定理3是如何表示? 相似文献
93.
A. O. Manyashin A. I. Fomenko V. N. Storozhenko N. T. Berberova 《Russian Journal of Electrochemistry》2003,39(11):1240-1244
Stoichiometry and kinetics of reactions of 2,6-diphenyl-4-chloropyrylium, 4-chloroflavylium, 4-bromoflavylium, and 4-iodoflavylium perchlorates with nucleophiles N,N-dimethylaniline and n-phenylenediamine are studied using cyclic voltammetry and spectroscopy. Nucleophilic substitution in these compounds proceeds via the formation of a charge-transfer complex, which converts into a radical ion pair as a result of the electron transfer. Heterolytic clevage of the C–Hal bond occurs at the stage of pyranyl (flavanyl) radical. 相似文献
94.
95.
LIU Hui-Min ZHANG Wei XIN Ying ZHANG Wen-Qin② 《结构化学》2004,23(5):532-536
1 INTRODUCTION We are presently involved in the synthesis and photodimerization of the analogues of trans-2-sty- rylbenzoxazole (BOEP), which have been widely reported as fluorescent whiteners and remedies[1]. Some structures of BOEP derivatives and thei… 相似文献
96.
Reduction of tetranuclear heterometallic complex Mo2Mg2 was simulated using the B3LYP and PBE density functional methods. The results of geometry calculations of the initial complex
[MoVIO2Mg(MeOH)2(OMe)4]2 and a partially reduced MoV complex are in good agreement with experimental data. The reduced MoIII complex is characterized by a decrease in the binding energy of aqua ligands. Structural rearrangement of the complex with
release of a coordination position at the Mo atoms requires small energy expenditure. One can assume that the reduction of
the polynuclear complex causes overcrowding of its coordination sphere, which favors formation of dinitrogen complexes.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 441–457, March, 2008. 相似文献
97.
Based on the previously developed technique using the Laplace transformation of distributions with compact support, we calculate the Hochschild cohomologies of the algebra of smooth functions on a finite-dimensional real vector space with coefficients in the adjoint representation. 相似文献
98.
The millimeter wave spectrum of the isotopically substituted CO dimer, (13C16O)2, has been studied for the first time, confirming and extending a recent infrared study. Eighty-seven transitions in the 77-180 GHz region have been assigned and analyzed in terms of a model-independent term value scheme involving 57 rotational levels with J=0-8. The levels can be classified into 7 “stacks” which have symmetry classifications of either A−/B+ or A+/B− and K-values of either 0 or 1. For the normal isotope, symmetry and nuclear spin statistics cause alternate rotational levels to be missing, but for (13C16O)2 all levels are present with an intensity alternation of 1:3 between A and B symmetries. The four A−/B+ stacks have not previously been observed, and the lowest of them establishes the tunneling splitting of (13C16O)2 to be 3.769 cm−1, slightly larger than the (12C16O)2 value of 3.731 cm−1. A large amount of precise experimental data is now available for the CO dimer, which should lead to greater theoretical insight into its structure and tunneling dynamics. 相似文献
99.
《Magnetic resonance in chemistry : MRC》2003,41(1):61-64
Palladium(II) dichloride reacts with 1,10‐bis(2‐pyrrolyl)‐2,5,9‐triaza‐1,9‐decadiene to give a [Pd(C15H20N5)]Cl complex in which the ligand is four‐coordinated, leaving one pyrrole group dangling. By using COSY, gHSQC, gHMBC connectivities and NOE experiments it has been concluded that one linkage isomer exists in DMSO solution, in spite of the fact that different sets of N atoms of potentially pentadentate ligand might be involved in coordination, and that the three chelate rings in the complex cation are arranged in a sequence: five‐membered, six‐membered, five‐membered which is different from that (5–5–6) found by x‐ray studies on the related [Ni(C15H20N5)]Cl compound. NMR studies allowed an unambiguous assignment of all 1H and 13C NMR resonances for the complex. Results of x‐ray structural analysis of [Pd(C15H20N5)](CH3COO)H2O supported the five‐membered, six‐membered, five‐membered ring sequence in the [Pd(C15H20N5)]+ complex cation and show an E (trans) orientation of the dangling pyrrole group with respect to the metal center. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
100.
合成了多个基于钴氰化锌的双金属氰化络合物(DMC)催化剂,并对催化剂的结晶形态进行了表征.考察了制备过程中,有机配体及其引入方式,温度,搅拌速度对DMC催化剂形态的影响.其中有机配体对DMC催化剂形态的影响是最主要的.有机配体中富电子原子的电负性的强弱和数量共同影响着DMC催化剂的形态.该类原子的电负性越强,得到的DMC催化剂的结晶性越差,无定型部分的比例越高,并且单个原子的电负性强弱比该类原子的数量在此间的影响更大.而在有机配体预先存在的情况下,该沉淀体系则更有利于无定型部分的产生.在30℃左右的沉淀反应温度下,得到的DMC催化剂的无定型部分比例最高.在有机配体存在的情况下,搅拌速度对DMC催化剂形态的影响有限.并且发现存在于有机配体中的DMC催化剂随着时间的推移,形态会发生变化.初步揭示了DMC催化剂的形态与其催化活性间的关系.而无定型态的DMC催化剂更有利于PO的聚合. 相似文献